---
id: CVE-2026-90021
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  usb: gadget: f_midi: initialize work in f_midi_alloc()

  f_midi_alloc initializes free_ref to 1 and it can only be incremented
  when a sound card is registered via f_midi…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  usb: gadget: f_midi: initialize work in f_midi_alloc()

  f_midi_alloc initializes free_ref to 1 and it can only be incremented
  when a sound card is registered via f_midi…
severity: medium
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 8653d71ce3763aedcf3d2331f59beda3fecd79e4 <
    3d8b11255e632170f32f1925bfcaf96331f36317
  - >-
    Linux >= 8653d71ce3763aedcf3d2331f59beda3fecd79e4 <
    02ac76f27db23ef652358458c272d9d2d6f51167
  - >-
    Linux >= 8653d71ce3763aedcf3d2331f59beda3fecd79e4 <
    858576de6b2f5166b08dae803f0fd0766dcb3002
  - >-
    Linux >= 8653d71ce3763aedcf3d2331f59beda3fecd79e4 <
    7e07d3e4c389217d7d7171d80edf2e23ac70f1ea
  - Linux 89019ab7a64fcdf98a2ba7799e5c6aff58d4a05d
  - Linux 3635523e9b96213969693c320302d536774d8e9b
  - Linux >= 5.4.291 < 5.5
  - Linux >= 5.10.235 < 5.11
  - Linux 5.12
published: '2026-09-16'
updated: '2026-09-16'
sourceUpdated: '2026-09-16T11:17:15.030'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-90021'
references:
  - url: 'https://git.kernel.org/stable/c/02ac76f27db23ef652358458c272d9d2d6f51167'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/3d8b11255e632170f32f1925bfcaf96331f36317'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/7e07d3e4c389217d7d7171d80edf2e23ac70f1ea'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/858576de6b2f5166b08dae803f0fd0766dcb3002'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-90021.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-90021'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2535407'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-90021'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-90021'
  - url: >-
      https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-90021.mbox
tags:
  - nvd
  - cve.org
  - csaf
  - vex
  - red-hat
ingestedAt: '2026-09-16T10:53:53.937Z'
cvss: 5.5
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'
cvssSource: vendor
cwe:
  - CWE-824
epss: 0.00209
epssPercentile: 0.0986
---

## Overview

In the Linux kernel, the following vulnerability has been resolved:

usb: gadget: f_midi: initialize work in f_midi_alloc()

f_midi_alloc initializes free_ref to 1 and it can only be incremented
when a sound card is registered via f_midi_register_card().
f_midi_register_card() is only called in f_midi_bind() which actually
performs INIT_WORK. If f_midi_bind() is never run, work is not
initialized and the if condition in f_midi_free becomes true,
this results in a warning later in __flush_work as work->func = 0.
Fix this by moving INIT_WORK from f_midi_bind() to f_midi_alloc().

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Vendor advisories

- **Red Hat VEX** · Moderate · updated 2026-09-17 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-90021.json)